The Whitby 45 is moderately powered for comfortable coastal cruising, with a steady, comfortable ride offshore, and respectable in club racing.
Hull Speed
The theoretical displacement-mode speed limit — determined by waterline length, not engine or sail power.
A displacement hull pushes a bow wave whose speed is limited by the waterline length.
With a waterline of 33.0′, the Whitby 45 tops out around 7.7 knots in displacement mode — after that, the bow wave outruns the hull and resistance climbs steeply.
1.34 × √33.0′ LWL = 7.7 kts
Performance Ratios
Racing handicap, sail-carrying power, stability and comfort — and what each one actually tells you about a day on the water.
PHRF Rating
102s/nm
Cruiser/racer — competitive in club racing, comfortable cruising.
SA / Displacement
17.7
Moderate sail power — a capable coastal cruiser, not overpowered.
Comfort Ratio
36.7
Good offshore comfort — steady enough for multi-day passages.
Capsize Screening
1.67
Below the 2.0 offshore threshold — acceptable for ocean passages.
Pounds/Inch Immersion
1lbs
Weight needed to sink the hull one inch — loading sensitivity.
Motion & Offshore Suitability
Two ratios that matter most when you're planning passages — how the boat feels in a seaway, and whether the hull geometry is suitable for open ocean.
Comfort Ratio
36.7
Good offshore comfort — steady enough for multi-day passages.
Under 20 — Snappy, racing motion
20–30 — Acceptable coastal
30–40 — Good offshore comfort
Over 40 — Very comfortable offshore
Capsize Screening Formula
1.67
Below the 2.0 offshore threshold — acceptable for ocean passages.
Under 2.0 — Acceptable for offshore
Over 2.0 — Coastal / protected waters
PHRF Fleet Position
Where the Whitby 45 sits on the PHRF handicap spectrum — lower numbers mean faster boats.
Racer 0–90
Cruiser/Racer 90–150
Cruiser 150–210
Whitby 45
102s/nm
Cruiser/racer — competitive in club racing, comfortable cruising.
Fuji 45
120s/nm
Formosa 46
128s/nm
Estimated Speed by Wind
Rough boat speed estimates at different true wind speeds and points of sail — derived from hull speed, SA/D, and displacement, not measured polars.
| Point of Sail |
6 kts TWS |
10 kts TWS |
15 kts TWS |
20 kts TWS |
| Close-hauled40–50° |
3.1 |
4.0 |
4.4 |
4.6 |
| Close Reach60° |
3.8 |
4.8 |
5.3 |
5.6 |
| Beam Reach90° |
4.6 |
5.9 |
6.6 |
6.8 |
| Broad Reach120–135° |
4.3 |
5.4 |
6.1 |
6.3 |
| Run150–180° |
3.4 |
4.3 |
4.8 |
5.1 |
These are simplified estimates based on hull speed (7.7 kts),
SA/D (17.7), and empirical efficiency curves — not instrument-measured
polars. Real-world speed varies with sea state, bottom condition, sail trim, and current.
Speeds in gold approach hull speed;
bold gold means near or at hull speed.
Wind Range & Comfort Envelope
Estimated wind ranges for comfortable sailing on the Whitby 45 — based on sail area, ballast, and displacement characteristics.
Ghost
Sweet Spot
Reef
Heavy
0–7 kts
7–20 kts
20–28 kts
28+ kts
Ghosting
0–7 kts
Light air, motor-sailing likely. Need patience and a light genoa.
Sweet Spot
7–20 kts
Comfortable under full sail. Best speed-to-comfort ratio.
Time to Reef
20–28 kts
Time to shorten sail. Reef the main, swap to a working jib.
Heavy Weather
28+ kts
Storm conditions. Storm jib or bare poles. Seek shelter if coastal.
How It Compares
Side-by-side with the boats most often cross-shopped against the Whitby 45.
|
Whitby 45 |
Apache 45 |
Formosa 46 |
Fuji 45 |
Irwin 45 |
Morgan 45 2 |
| Dimensions |
| LOA |
45.0 |
45.0 |
45.0 |
45.0 |
45.0 |
45.0 |
| LWL |
33.0 |
41.0 |
39.6 |
33.0 |
32.0 |
39.3 |
| Beam |
12.0 |
19.5 |
12.9 |
12.7 |
11.5 |
13.3 |
| Displacement |
23 |
14 |
33 |
30 |
23 |
30 |
| Ballast |
11 |
— |
10 |
8 |
10 |
— |
| Sail Area |
913 |
710 |
911 |
997 |
882 |
734 |
| Performance |
| PHRF |
102 |
— |
128 |
120 |
— |
— |
| SA/Disp |
17.7 |
19.6 |
14.2 |
16.4 |
17.5 |
12.2 |
| Bal/Disp |
— |
— |
30.3 |
28.7 |
43.5 |
— |
| Comfort |
36.7 |
9.7 |
41.0 |
43.8 |
38.3 |
36.0 |
| Capsize |
1.67 |
3.24 |
1.61 |
1.63 |
1.62 |
1.72 |
| Hull Speed |
7.7 |
— |
8.4 |
7.7 |
7.6 |
8.4 |